I'd start building towards a battle demi-company and go from there. a demi-battle company would enable you to build eaither a gladius or the Sternhammer strike force.
maybe consider something along these lines:
Strike Force (works as gladius or sternhammer)
1 Demi Battle Comapny:
Lysander 230 points
3
Tac Marine Squads In rhinos (approx 175 points)
1 Centurion assault squad with hurricane bolters and melta guns (approx 170 points)
1 Devestator Squad with Razor Back (kitted as you like, I'm pricing under the assumption of 4 grav cannons and Las canon turret) 285
1 Contemptor Dreadnought (170 points)
1st Company Task Force
2 Squads of cataphracti Terminators 175 pts each
1 Sternguard Squad with Razorback 145 pts
total approx points: 1875 points
you could proably get the points reduced back down to in the 1700s if you went with devestator centurions instead of a devestator squad. I wanted to give you more options to use your transports
please note this list isn't intended to be super compeitive, just a good place to move in the direction of if your looking to use what you have to have a good starting place.